Containerized Power Flow Control Systems

ABSTRACT

A containerized power flow control system is described, for attachment to a power transmission line or substation. The system includes at least one container that is transportable by road, rail, sea or air. A plurality of identical impedance injection modules is operable while mounted in the container, wherein each of the modules is configurable to inject a pre-determined power control waveform into the power line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/634,057 filed Feb. 22, 2018, the entirety of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to containerized solutions for installing powerflow control systems on the electric grid.

2. Prior Art

Modular power flow control systems have been developed, wherein themodules may incorporate power transformers, or may be transformerless,such as those employing transformerless static synchronous seriesconverters (TL-SSSCs). Such modular systems are normally intended forpermanent deployment and involve non-standard components in hardware aswell as in software customized to specific sites, thereby requiring longlead times, typically years, for planning, design, construction andinstallation. Such systems are not designed for ease of shipping andfast installation, and therefore are not suitable for emergencysituations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a power distribution system comprising atransmission line mesh, with each branch of the mesh comprising threephases, and each phase having a distance relay provided at each end ofeach branch.

FIG. 2 is a schematic showing an exemplary power flow control systemcomprising transformer-based impedance injection modules installed on aphase of a power distribution system.

FIG. 3 is a schematic showing an exemplary power flow control systemcomprising transformer-less impedance injection modules installed on aphase of a power distribution system.

FIG. 4 is a block diagram of an exemplary impedance injection module, asused in embodiments of the present invention.

FIG. 5 is a schematic view of a containerized power flow control systemoperating from two containers, each container carried on a trailer.

FIG. 6 is a schematic view of an exemplary trailer-based installation ofa power flow control system.

FIG. 7 shows a container deployed in an embodiment of the presentinvention.

FIG. 8 is an expanded view of stowed equipment in a container deployedin an embodiment of the present invention.

FIG. 9 shows impedance injection modules lifted to the roof of acontainer deployed in an embodiment of the present invention.

FIG. 10 shows an insulator post lifted to the base of an impedanceinjection module deployed in an embodiment of the present invention.

FIG. 11 shows lifting of impedance injection modules to a midway height,in an embodiment of the present invention.

FIG. 12 shows rotated impedance injection modules in an embodiment ofthe present invention.

FIG. 13 shows a container with fully deployed impedance injectionmodules in an embodiment of the present invention.

FIG. 14 is a view of electrical connections from containerized equipmentto a transmission line tower, in an embodiment of the present invention.

FIG. 15 is a flow chart of an installation method of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Thus, it is desirable to create a new type of portable, modular,containerized power flow control solution wherein each module iscontainerized and designed to make the portable power flow controlsystem simple to transport, install, operate, and scale.

Disaster relief areas and areas affected by blackouts may require arapid deployment of a power flow control system to stabilize the powerdistribution system in the area. Typically, containerized Flexible ACTransmission Systems (FACTS) devices of the present invention aredeployed to substations or to high voltage transmission line areas.Power flow control issues may include: specific, planned constructionsupport; non-specific, unplanned construction support; emergencytransmission support; short-term interconnection; short-term congestion;maintenance outages; and, emergency response to weather events.Additionally, areas where new installations of electric power are neededor where permits or land area are difficult to obtain may also benefitfrom a modular, containerized, compact, easy-to-transport andeasy-to-install solution. The permitting process may require both PublicUtilities Commission (PUC) and International Standards Organization(ISO) approval. Furthermore, since the needs of the grid change overtime, a portable solution provides a utility with the flexibility itneeds to adapt to unpredicted changes in the power system.

The container itself may be an ISO 40×8×8.5-foot container, or anyvariant that is allowed on highways or defined by alternative shippingsystems. The power flow control devices may be loaded into thecontainers in various configurations to be maximized for energy densityand may include equipment corresponding to one or three phases within acontainer. Each container may include multiple impedance injectionmodules, at least one bypass switch, insulation and support equipment,and interconnection component (interconnection equipment). As anexample, each impedance injection module shown in FIG. 3 may beconfigured to inject 2 kVAR of reactive power per kilogram weight of theimpedance injection module. Multiple containers may be used for a fullmobile power flow control system solution.

A containerized FACTS module of the present invention may modify asystem variable of a power system, typically reactive power. Thecontainerized module typically also includes control devices, faultprotection devices, a communication subsystem for communicating with theexisting power distribution system, and an interconnection component.

Regarding the interconnection component, transmission lines typicallyend at substations and are supported by terminal deadend structures thatare designed to take the full conductor tension load. Substationsmaintain controlled access and have security access protocols to ensureonly authorized personnel can enter the site. The interconnectioncomponent that may be carried in an interconnection trailer is typicallydesigned to tap to either the conductors or bus work inside thesubstation. As part of the interconnection process, the line may need tobe physically disconnected by removing a jumper, replacing an existingconnection, or splicing a strain insulator onto the conductor.Substations typically have limited areas available for installations,thus, another design option is to install the containerized FACTSmodules directly onto a free-standing transmission line. In thisembodiment, the ground terrain is varied, and the transport system mustaccommodate a wide variety of terrains. One deployment option is to tapnear a deadend structure; these are typically found at line angles orcrossings. Deadend structures may have a jumper which is a slacked spanconductor that connects the end of two strain insulators to maintainelectrical clearances to the structure. Alternatively, splicing a straininsulator onto the conductor creates a location to aerial tap theconductors mid span between structures.

While the above discussion shows that possible configurations of acontainerized power flow control system are many and varied, severaluseful configurations are described herein for specificity. A person ofordinary skill in the art will understand that these examples are notlimiting, and that many combinations and variations of the describedcontainerized power flow systems are possible.

FIG. 1 shows a power distribution system 10 spanning between a pair ofsubstations 11 a and 11 b. Power distribution system 10 comprises a meshnetwork of transmission lines having three phases per branch, 12 a, 12b, 12 c. Each single phase 13 of a three-phase branch typically has adistance relay 14 at each end. The distance relays represent a primaryprotection system in many power distribution systems.

FIG. 2 shows details of a power flow control system 20 installed in asingle phase 13 of a power transmission line such as shown in FIG. 1. Abreak in Phase 13 is achieved using a strain insulator 24 as shown.Disconnect switches 21 a and 21 b are shown, for routing power duringinstallation, and providing protection to the installation crew. Aplurality of impedance injection modules 22 are shown, eachincorporating a power transformer. A bypass switch 23 is also shown,providing a means to bypass the impedance injection modules formaintenance or repair for example.

FIG. 3 shows details of another power flow control system 30 installedin a single phase 13 of a power transmission line such as shown inFIG. 1. A break in Phase 13 is achieved using a strain insulator 24 asshown. An m×n matrix 31 of impedance injection modules is shown, where mequals the number of impedance injection modules 32 connected in seriesin each of n parallel branches 33 a and 33 b. In FIG. 3, m=4 and n=2. Abypass switch 34 is also shown, providing a means to bypass the parallelconnected series of impedance injection modules for maintenance orrepair for example. In FIG. 3, each of the impedance injection modules32 may be a transformerless static synchronous series converter(TL-SSSC) for example.

Impedance injection modules 22 and 32, and bypass switches 23 and 34 areexemplary components of Flexible AC Transmission Systems (FACTs).

FIG. 4 is a block diagram of a typical impedance injection module 40that communicates wirelessly 41 with an external support system 42.Support system 42 may have supervisory control over the powerdistribution system 10 of FIG. 1. Impedance injection module 40comprises a communication and control subsystem 43 including an antenna44, a transceiver 45, a microprocessor 46 and a memory 47. Memory 47contains instructions executable by microprocessor 46 for configuring,controlling, and reporting out of impedance injection module 40. Duringoperation, microprocessor 46 commands a power switching assembly 48 thatconnects impedance injection module 40 into phase line 13, to implementa power flow control system such as 20 of FIG. 2 or 30 of FIG. 3. In atypical containerized system in accordance with the present invention,each FACTS device, impedance injection module or not, includes a similarcommunication and control subsystem so that the support system may havesupervisory control over the entire containerized power flow controlsystem and the FACTS devices therein, and preferably in coordinationwith the rest of the power distribution system.

FIG. 5 shows a pair of trailers carrying containers 51 and 52 forinstallation of a portable power flow control system such as 20 of FIG.2 or 30 of FIG. 3. Container 51 carries a matrix of m×n impedanceinjection modules such as 22 of FIG. 2 or 32 of FIG. 3. Container 52carries a bypass switch such as 23 of FIG. 2 or 34 of FIG. 3. The powerflow control equipment shown in containers 51 and 52 remains resident inthe respective container during operation of the transmission line(phase) 13, such as depicted in FIG. 1. By using standardized impedanceinjection modules such as 22 of FIG. 2 or 32 of FIG. 3, they can bedeployed quickly in an active power distribution system such as 10 ofFIG. 1. After operation for a period of days, weeks, months, or years,these impedance injection modules can be redeployed in another portablepower flow control system having different requirements. Thus, inembodiments of the present invention, mobile containerized power flowcontrol systems can be deployed rapidly and effectively, and thenredeployed rapidly and effectively, to provide versatile andcost-effective power flow control measures under varying fieldconditions.

FIG. 6 illustrates a portable power flow control system 60 comprising 4trailers 61 a, 61 b, 61 c and 61 d. Trailer 61 a holds switchgear,trailer 61 b holds impedance injection modules, and trailers 61 c and 61d hold supporting connection electronics and a relay and a protectionconfiguration.

FIG. 7 shows a containerized module 70. Containerized module 70 includesa standard ISO container 71 that is carried on a trailer with wheels 72,and the trailer is stabilized by outriggers 73.

FIG. 8 shows a compartment 80 a of container 71, with stowed flowcontrol system components inside. Contained within compartment are apair of impedance injection modules 22 a(1) and 22 b(1), an insulatorpost 81 a and a roof platform 82.

FIG. 9 shows compartment 80 b wherein impedance injection modules 22a(1) and 22 b(1) have been raised to the roof position using a lifterwhere they are labeled 22 a(2) and 22 b(2). Since impedance injectionmodules 22 a(2) and 22 b(2) may weigh around 3600 pounds in someembodiments, a hydraulic lifter may be used. Other types of liftersincluding a crane may also be used.

FIG. 10 shows compartment 80 c wherein insulator post 81 a has beenlifted up to interface with impedance injection module 22 b(2) and islabeled 81 b in its new location.

FIG. 11 depicts a mid-way lift of the two impedance injection modulesshown in FIGS. 8-10, together with their insulator posts. At thisintermediate height, electrical connections to the impedance injectionmodules may conveniently be made by a member of the installation crew.

FIG. 12 shows that the two impedance injection modules have beenrotated, in this case by 90 degrees. Other rotation angles may be used.This rotation may be utilized to improve electrical clearances betweencomponents of the two modules.

FIG. 13 shows three pairs of impedance injection modules that have beenraised to the final deployment height, following their electricalconnection. A lower cost installation procedure is made possible bylifting the impedance injection modules two at a time. Since this finalraising of the impedance injection modules is performed after electricalconnections have been made, and since the electrical connections involvestiff and unyielding components, to minimize mechanical stress there isa tolerance of around 12 mm for the final height of each impedanceinjection module. As an example, this tolerance may be achieved using ahydraulic lifter with an equalization valve for equalizing the hydraulicpressure at each of the two individual lifters. Alternative lift systemsmay comprise simultaneous lifting of a pair of modules using a screwdrive system, simultaneous lifting of up to 10 modules using a pressureequalizing valve system, or simultaneous lifting of up to 10 modulesusing a screw drive system, wherein each of a plurality of screw drivesis mechanically coupled to the other screw drives of the screw drivesystem.

FIG. 14 shows some of the electrical connections to be made at aninstallation 140 of a power flow control system of the presentinvention, in the vicinity of a transmission line tower 141. Trailers142, 143, 144 and 145 are shown. Trailer 142 contains a disconnectswitch such as 21 a of FIG. 2. Trailer 143 contains a set of impedanceinjection modules such as set 131 of FIG. 13. Trailers 144 and 145contain a second and a third disconnect switch in this embodiment. Ajumper cable 146 is shown connecting between a conductor at the end of astrain insulator 147 and a post insulator 148, and further connecting tothe third disconnect switch in trailer 145, with a portion captured byriser structures 149. To describe the possible power routings, we shallfocus on Phase A only. Phase A(1) can be connected to Phase A(2) usingthe third disconnect switch contained in trailer 145, without passingthrough the impedance conversion modules contained in trailer 143 byopening disconnect switch in trailer 142 and 144. Alternatively, PhaseA(1) can be connected through the disconnect switches contained intrailer 142 and 144 to associated impedance injection modules in trailer143, and with disconnect switch 145 open to Phase A(2), in order toconnect the mobile power flow control system into Phase A of thetransmission line. The disconnect switches are rated at line voltagestypically between 69 kV and 345 kV.

It should be noted that the word module as used herein has been used ina general, usually functional sense as an extension of the word modularto emphasize the fact that a complete power flow control system may beassembled by interconnecting multiple modules, though such modules mayor may not be self-contained within their own separate case or housing,but are within or supported by a respective container for transport andas well as when in operation. Also generally the modules or functionalcomponents within a container are used together, usually in combinationwith the modules or functional components in one or more othercontainers.

FIG. 15 is a flow chart 150 of an installment method of the presentinvention, comprising: packing a container with power flow controlequipment, including impedance injection modules, step 151; transportingthe container to a desired work location, step 152; deploying outriggersto stabilize the container in the work location, step 153; lifting theimpedance injection modules to an intermediate height, step 154;rotating certain ones of the impedance injection modules as required,step 155; making electrical connections to the impedance injectionmodules, step 156; and, lifting the impedance injection modules to theirfinal deployment height, step 157.

Thus the present invention has a number of aspects, which aspects may bepracticed alone or in various combinations or sub-combinations, asdesired. Also while certain preferred embodiments of the presentinvention have been disclosed and described herein for purposes ofexemplary illustration and not for purposes of limitation, it will beunderstood by those skilled in the art that various changes in form anddetail may be made therein without departing from the spirit and scopeof the invention.

What is claimed is:
 1. A container for use in a containerized power flowcontrol system for a high voltage power distribution system comprising:the container containing at least one FACTS device for deployment on anas needed basis; the container and the FACTS device being adapted forcoupling the FACTS device into a high voltage power distribution systemand operating while remaining in or being supported by the container. 2.The container of claim 1 wherein the container includes a container roofplatform for supporting the FACTS device in preparation for coupling theFACTS device into a high voltage power distribution system.
 3. Thecontainer of claim 1 further comprised of at least one insulator forsupporting the FACTS device above the container when coupled into a highvoltage power distribution system.
 4. The container of claim 3 whereinthe container also contains a lifter for lifting the insulator with theFACTS device thereon to an elevation wherein the FACTS device isdisposed in an operative elevation above the container.
 5. The containerof claim 1 wherein the container contains multiple FACTS devices.
 6. Thecontainer of claim 5 wherein the container also contains a bypassswitch.
 7. The container of claim 5 wherein the FACTS devices are orinclude one or more impedance injection modules.
 8. The container ofclaim 5 wherein the FACTS devices are or include one or moretransformerless static synchronous series converters.
 9. The containerof claim 1 wherein the container contains at least one disconnectswitch.
 10. The container of claim 1 wherein the container is a PUC andISO approved container.
 11. The container of claim 1 wherein thecontainer is mounted on a trailer.
 12. The container of claim 11 whereinthe trailer includes outriggers for stabilizing the trailer.
 13. Thecontainer of claim 1 wherein the container further contains controldevices, fault protection devices, a communication subsystem forcommunicating with an existing power distribution system, and aninterconnection component.
 14. The container of claim 1 wherein thecontainer is configured for transport by air, sea, rail and highway. 15.A containerized power flow control system for a high voltage powerdistribution system comprising: a plurality of containers, eachcontaining at least one FACTS device for deployment on an as neededbasis; the containers and the FACTS devices being adapted for couplingthe FACTS devices into a high voltage power distribution system andoperating while remaining in or being supported by the respectivecontainers.
 16. The system of claim 15 wherein at least one containercontains a bypass switch.
 17. The system of claim 15 wherein the FACTSdevices include a plurality of impedance injection modules.
 18. Thesystem of claim 17 wherein at least one container contains a matrix ofm×n impedance injection modules.
 19. The system of claim 15 wherein theFACTS devices include a plurality of transformerless static synchronousseries converters.
 20. The system of claim 15 wherein at least somecontainers contain multiple FACTS devices.
 21. The system of claim 15wherein the containers are PUC and ISO approved containers.
 22. Thesystem of claim 15 wherein the containers are on trailers.
 23. Thesystem of claim 22 wherein at least some of the trailers includeoutriggers for stabilizing the trailers.
 24. The system of claim 15wherein at least one container also contains an insulator for holding atleast one FACTS device above the container.
 25. The system of claim 24wherein the container containing the insulator also contains a lifterfor lifting the insulator with the FACTS device thereon to an elevationwherein the FACTS device is disposed in an operative elevation above thecontainer.
 26. The system of claim 15 wherein each container furthercontains control devices, fault protection devices, a communicationsubsystem for communicating with an existing power distribution system,and an interconnection component.
 27. The system of claim 15 wherein thecontainers are configured for transport by air, sea, rail and highway.28. A containerized power flow control system comprising: a plurality ofcontainers, each containing or supporting at least one FACTS devicewithin a variety of FACTS devices in the containers, the FACTS devicesbeing connected into a high voltage power distribution system, thevariety of FACTS devices including impedance injection modules, at leastone bypass switch and at least two disconnect switches, the disconnectswitches being disposed in the power control system for electricallydisconnecting the impedance injection modules from the high voltagepower distribution system, the bypass switch being disposed in the powercontrol system for controllably bypassing current flow around the otherFACTS devices in the containerized power flow control system.
 29. Thesystem of claim 28 wherein the impedance injection modules aretransformerless static synchronous series converters.
 30. The system ofclaim 28 wherein each FACTS device includes a communication and controlsubsystem for supervisory control by a support system.
 31. The system ofclaim 28 wherein at least some of the containers are on trailers. 32.The system of claim 28 wherein at least one of the trailers hasoutriggers extended for stabilizing the trailer.